<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>并集选择器</title>
    <style type="text/css">
        h2, h3, p {color:gray; font-size:14px;} /*由不同标签选择器组成的并集选择器*/
        h3, .special, #one {text-decoration:underline;} /*由标签选择器、类选择器、id选择器组成的并集选择器*/
    </style>
</head>
<body>
    <h2>2级标题文本</h2>
    <h3>3级标题文本</h3>
    <p class="special">段落文本1</p >
    <p>段落文本2</p >
    <p id="one">段落文本3</p >
</body>
</html>